• Volume 91, Issue 1

      February 1982,   pages  1-77

    • Thaxteriellopsis lingicola and itsMoorella anamorph

      C V Subramanian G Sekar

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      AMoorella anamorph referable toM. speciosa Rao and Rao, is described forThaxteriellopsis lignicola Sivanesan, Panwar and Kaur. The connection is established from a study of single ascospore cultures of the fungus established for several (6) South Indian collections. Both the teleomorph and anamorph are described and brief notes are given of characteristics of this fungus in culture.

    • A contribution to the embryology ofAlysicarpus monilifer D.C.

      V Seshavatharam

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      Embryology ofAlysicarpus monilifer D.C. is described. The anther wall comprises the epidermis, the fibrous endothecium, two middle layers and uniseriate glandular tapetum. Pollen is shed at the 2-celled stage. The ana-campylotropus ovule is crassinucellate and bitegmic. The archesporium in the ovule is hypodermal and cuts off a parietal cell. Embryo sac development conforms to the Polygonum type. Endosperm development is nuclear. A chalazal part of the endosperm remains free nuclear and is haustorial in function. Embryogeny conforms to Period I Megarchetype IV and Series B2. The embryogenic classification of the tribe is discussed in the light of the present observation and earlier reports.

    • Non-inheritance of isomerism in cocoyams

      T Venkateswarlu

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      The present communication describes the non-inheritance of isomerism in prefoliation and contortion of spathes in cocoyams. Importance of isomerism from the point of taxonomy and agronomy has been discussed. It is expected that a study on the orientation of leaf promordia at shoot apex and their spiral descendance would help in unravelling the hidden laws in shoot morphogenesis of cocoyams.

    • Apomixis inCenchrus glaucus Mudaliar et Sundaraj

      C Shanthamma

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      A detailed cytoembryological investigation inCenchrus glaucus revealed that it is an obligate apomict producing only aposporous embryosacs. Microsporogenesis disclose chromosomal irregularities and megasporogenesis occasionally occur and the development of sexual embryosac is completely absent. On the other hand, aposporous initials develop into 4-nucleate embryosacs. Autonomous development of the embryo is of common occurrence.

    • Regeneration of plantlets from callus ofElettaria cardamomum Maton

      N K Srinivasa Rao S Narayanaswamy E K Chacko R Dore Swamy

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      Embryo callus and callus of rootstocks ofin vitro-raised seedlings ofElettaria cardamomum were grown on MS medium supplemented with CW+2, 4−D+BAP. Differentiation of shoot buds, roots and leaves leading to the development of plantlets could be induced in callus by withdrawing 2, 4−D or substituting it by IAA or NAA in low concentrations.

    • Studies in Cyperaceae: XVII Novelties inFimbristylis (L.) Vahl and their vegetative anatomy

      E Govindarajalu

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      Two novelties ofFimbristylis collected from Tamil Nadu (Madras State) are described and illustrated. One of them belongs to the sectionFuscae and the other one toCymosae. The vogetative anatomical characters of these two novelties not only fall within the ambit of the range of anatomical variability of the genus as a whole but their respective anatomical features in combination appear to be characteristic and different from those of the species already known anatomically.

    • Embryological studies in three species ofCymbopogon Spreng (Poaceae)

      S P Choda Harsh Mitter Ravinder K Bhanwra

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      The embryology ofCymbopogon nardus var.confertiflorus, C. martinii var.Motia andC. parkeri has been studied.C. nardus andC. martinii have been observed to be seed-sterile owing to failure of fertilization while inC. parkeri, the seed-setting is only about 8·00%.

    • Reproductive efficiency of secondary successional herbaceous population subsequent to slash and burn of sub-tropical humid forests in north-eastern India

      K G Saxena P S Ramakrishnan

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      Three categories of secondary successional herbaceous communities subsequent ot slash and burn, viz., early successional non-sprouting, early successional sprouting and late successional populations were investigated for their reproductive efficiency considering leaf component since it is the chief organ of photosynthesis. Early successional non-sprouting populations were found to be reproductively the most efficient whereas the early successional sprouting populations allocated more to vegetatively reproducing organs. While the high reproductive potential of early successional non-sprouting species was associated with vigour and production efficiency of the species, this relationship was stronger with the latter characteristic. On the other hand, early successional sprouting populations showed inverse relationship between vegetative and sexual reproductive effort. The strategy of late successional species seems to be to maximize vegetative growth in a closed habitat. The significance of these strategies is discussed in the paper.

    • Vesicular arbuscular mycorrhiza in subtropical aquatic and marshy plant communities

      R Chaubal G D Sharma R R Mishra

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      Occurrence of vesicular arbuscular mycorrhiza in five subtropical ponds, i.e., eutrophic (P1,P2 andP3), running water (P4), oligotrophic lake (P5) and marshy plant community (M) was studied. It was observed that the plants growing inP1,P5 andM habitats exhibited the vesicular mycorrhizal association, whereas the fungal association was lacking in plants ofP2,P3 andP4 ponds. The endogonaceous spore population was estimated from water and sediments of the different ponds and it, was found that endophytes in sediments are less in terrestrial habitats and completely absent from water samples. The bioassay studies revealed that plants without mycorrhizal association grew poorly and all the endophytes isolated could establish vesicular arbuscular mycorrhizal associations in pot cultures.

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